Question

I am a beginner of android, and was studying the layout.

What i am trying to do is i am trying to add a textView to a LinearLayout through code, and the application stops with the error that the application has stopped unexpectedly. The code is:

    setContentView(R.layout.main);

    LinearLayout abc = (LinearLayout)findViewById(R.id.cLayout);

    TextView tv = new TextView(this);
    tv.setText("Text Changed!!!!");

    abc.addView(tv);

And in the xml, id is set like: android:id=”@+id/cLayout”.

I know there are better ways to do it, but i want to know why this doesn’t work. Contents of textView are changing just fine. Also i have also tried

    LinearLayout abc = (LinearLayout)findViewById(R.layout.main);

What am i doing wrong? One thing is clear that i am accessing uncreated items (unassigned pointer).

Edit
Main xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:id="@+id/cLayout"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="Hello World"
    android:id="@+id/myTV"
    />
</LinearLayout>

Answer 1

I’ve tried to reproduce it, and it works for me, no exceptions.

main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
          android:id="@+id/cLayout"
          android:orientation="vertical"
          android:layout_width="fill_parent"
          android:layout_height="fill_parent">
    <TextView  
          android:layout_width="fill_parent" 
          android:layout_height="wrap_content" 
          android:text="Hello World, MyActivity"/>
</LinearLayout>

MyActivity.java:

public class MyActivity extends Activity
{
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        LinearLayout ll = (LinearLayout) findViewById(R.id.cLayout);

        TextView tv = new TextView(this);
        tv.setText("Hello Again!");

        ll.addView(tv);
    }
}

UPD When I posted your code, I got an exception, too. Make sure you call super.onCreate().